Can I use MFC with BC++?

Microsoft Foundation Classes (MFC)
To support existing projects built with Microsoft Foundation Classes, C++ Builder both supports and includes MFC version 6 for compatibility with Visual C++ version 6 and earlier.

Apparently so. Well, at least the Borland C++ Builder does; I'm not sure that the free compiler does. But the C++ Builder Personal edition is only $69 as compared to $109 for MSVC++ .NET, so if you're looking for MFC that might be the cheapest option.